Tracing Galaxy Formation with Stellar Halos. II. Relating Substructure in Phase and Abundance Space to Accretion Histories

By K. Johnston, James S. Bullock, Sanjib Sharma, A. Font, Brant Robertson, Samuel N. Leitner. 2008

303 citations recorded by the source corpus.

This paper explores the mapping between the observable properties of a stellar halo in phase and abundance space and the parent galaxy’s accretion history in terms of the characteristic epoch of accretion and mass and orbits of progenitor objects. The study utilizes a suite of 11 stellar halo models constructed within the context of a standard ΛCDM cosmology. The results demonstrate that coordinate-space studies are sensitive to the recent (0-8 Gyr ago) merger histories of galaxies (this timescale corresponds to the last few percent to tens of percent of mass accretion for a Milky Way-type galaxy). Specifically, the frequency, sky coverage, and fraction of stars in substructures in the stellar halo as a function of surface brightness are indicators of the importance of recent merging and of the luminosity function of infalling dwarfs. The morphology of features serves as a guide to the orbital distribution of those dwarfs. Constraints on the earlier merger history (>8 Gyr ago) can be gleaned from the abundance patterns in halo stars: within our models, dramatic differences in the dominant epoch of accretion or luminosity function of progenitor objects leave clear signatures in the [α/Fe] and [Fe/H] distributions of the stellar halo; halos dominated by very early accretion have higher average [α/Fe], while those dominated by high-luminosity satellites have higher [Fe/H]. This insight can be applied to reconstruct much about the merger histories of nearby galaxies from current and future data sets.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b43521703cc3d9814706e1133f098be50bc0a3f3

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Citations in the corpus

LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) — The survey's science plan (2012, background): “The chemical signatures of accretion events persist to some extent in [Fe/H], but can beseen much more clearly in alpha-element abundances (i.e., [α/Fe]), which carry the imprint of the progenitor’s enrichment history and can be used to identify accretion events (or more generally, a global accretio”
Cosmological simulations of the formation of the stellar haloes around disc galaxies (2011, background): “…theoretical studies suggest that the main properties of stellar haloes can be explained entirely by the accretion and disruption of satellites (Bullock & Johnston 2005; Font et al. 2006a,b,c; De Lucia & Helmi 2008; Font et al. 2008; Johnston et al. 2008; Gilbert et al. 2009b; Cooper et al. 2010).”
THE GHOSTS SURVEY. I. HUBBLE SPACE TELESCOPE ADVANCED CAMERA FOR SURVEYS DATA (2011, background): “As substructure is more readily identified in the outer regions (Johnston et al. 2008), we can thus place limits on the presence of a uniform low-metallicity halo beneath the remnants of recent accretion events.”
THE LARGE-SCALE STRUCTURE OF THE HALO OF THE ANDROMEDA GALAXY. I. GLOBAL STELLAR DENSITY, MORPHOLOGY AND METALLICITY PROPERTIES (2013, background): “The variations in metallicity, size, and orbit highlight differences in mass, age, and accretion time (see, e.g., Johnston et al. 2008).”
Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud (2019, background): “Ultimately, the phase space information of halo tracers can inform us about the underlying DM potential, the total mass, and the accretion history of the MW (Johnston et al. 2008; Helmi 2008; Gómez et al. 2010; Carlin et al. 2016).”
LIGHT CURVE TEMPLATES AND GALACTIC DISTRIBUTION OF RR LYRAE STARS FROM SLOAN DIGITAL SKY SURVEY STRIPE 82 (2009, methodology): “Simulations by Johnston et al. (2008) predict that the metallicity of low surface brightness features, such as the Virgo Overdensity (Jurić et al. 2008), is expected to be lower than the median halo metallicity.”
Galaxy formation theory (2010, background): “…to the build-up of the Milky Way’s stellar halo (Cooper et al. 2009), and there may be remnant tidal streams which could provide information about the hierarchical growth of the Milky Way’s halo (Bullock and Johnston 2005; Robertson et al. 2005; Font et al. 2006a,b; Johnston et al. 2008).”
Chemical signatures of formation processes in the stellar populations of simulated galaxies (2011, background): “Some simulations have suggested that stellar haloes may have formed primarily through satellite disruption (e.g. Johnston et al. 2008; Cooper et al. 2010), but there have also been claims for a dual formation route, depending on the early merging history of each individual galaxy (e.g. Zolotov et…”
STELLAR TIDAL STREAMS IN SPIRAL GALAXIES OF THE LOCAL VOLUME: A PILOT SURVEY WITH MODEST APERTURE TELESCOPES (2010, background): “The current models predict that a survey of between 50 and 100 parent galaxies reaching to a surface brightness of ∼ 30mag/arcsec2 should reveal many tens of tidal features, perhaps nearly one detectable stream per galaxy (Bullock & Johnston 2005; Johnston et al. 2008; Cooper et al. 2010).”
Illuminating Low Surface Brightness Galaxies with the Hyper Suprime-Cam Survey (2017, methodology): “Tidal Debris At the depths of HSC-SSP, galaxy interactions produce rich networks of LSB substructure and tidal debris, as predicted by the ΛCDM cosmological framework (Bullock & Johnston 2005; Johnston et al. 2008; Cooper et al. 2010).”
Ultra–Low Surface Brightness Imaging with the Dragonfly Telephoto Array (2014, background): “Detailed simulations of tidal debris around Milky Way-like galaxies (Johnston et al. 2008; Cooper et al. 2010) and elliptical galaxies (Naab et al. 2007) indicate that the majority of accreted stars live at surface brightness levels & 29 mag arcsec−2.”
HIGH-RESOLUTION SPECTROSCOPY OF EXTREMELY METAL-POOR STARS IN THE LEAST EVOLVED GALAXIES: URSA MAJOR II and COMA BERENICES (2009, background): “The chemical evolution model of Robertson et al. (2005), Font et al. (2006), and Johnston et al. (2008) predicts that, although massive dwarf galaxies are the source of the vast majority of the mass in the stellar halo, low luminosity, metalpoor, galaxies accreted at early times contribute some…”
THE DUAL ORIGIN OF STELLAR HALOS (2009, background): “Their work has been highly successful in explaining the discrepant chemical abundances of Milky Way satellite galaxies and field halo stars (Font et al. 2006a, 2006b; Johnston et al. 2008).”
THE RELATIONSHIPS AMONG COMPACT STELLAR SYSTEMS: A FRESH VIEW OF ULTRACOMPACT DWARFS (2011, background): “Galaxy-to-galaxy variations in the prevalence of these two populations (e.g., NGC 1399 vs. M87; Mieske et al. 2006a) might then reveal differences in star formation history and galaxy assembly (cf Johnston et al. 2008).”
KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS (2012, background): “Six halos that we consider are with accretion events being dominated by 1) radial orbits 2) circular orbits 3) old events 4) recent events 5) higher luminosity and 6) low luminosity and these are from simulations of Johnston et al. (2008).”
CHEMICAL EVOLUTION IN HIERARCHICAL MODELS OF COSMIC STRUCTURE. II. THE FORMATION OF THE MILKY WAY STELLAR HALO AND THE DISTRIBUTION OF THE OLDEST STARS (2009, methodology): “More information about the formation of the satellites and their role in building the stellar halo is available from theoretical modeling of chemical abundances; see in particular the series of papers by Font et al. (2006a,b, 2008) and Johnston et al. (2008).”
METALLICITY EVOLUTION OF DAMPED Lyα SYSTEMS OUT TO z ∼ 5 (2012, methodology): “We compare the stars to DLAs withz> 2, as the majority of the halo stars are believed to have formed by then (Freeman & Bland-Hawthorn 2002; Bullock & Johnston 2005; Robertson et al. 2005; Johnston et al. 2008).”